It's a fool's errand-but this quest through the dark woods is the only chance Allie has of ever feeling at home again.

Mary Granderson's body was never found after a tornado swept through the town of Mattingly. For her daughter Allie, each of the 542 days since have robbed her of a bit more hope that her mother will come home. Allie's father has turned to drink in a failed effort to contain his grief. What light still shines in Allie's life comes from three things: her best friend Zach, the broken compass Mary gave her just before the tornado struck, and the nativity scene that has sat in their front yard ever since-mother, father, and child together.

Allie wakes one morning to find Mary missing from the nativity-taken, she believes, by her father in an attempt to force Allie to move on. Amidst her panic and grief, Allie discovers that the compass on her wrist-broken since the tornado-is now functioning, and the needle points not north, but to Mary.

Accompanied by Zach and her dog, the compass leads Allie away from town into the wilderness surrounding Mattingly. As the children wander farther into the dark woods, they find themselves lost and cold and they slowly discover they're not alone. Something is following them, something that shouldn't be there. And it will take all the courage and sacrifice that two children can summon to not only save themselves, but to bring Mary home.